Question

Ajutati_ma va rog imi trebuie urgent.Calculati: 3 -1 supra 4+2supra 3 ; 3supra5 - 1supra15 +4 supra5; 1 supra 5 -1 supra 6 + 1 supra 15 ; 5 supra 8 - 1 supra 5 + 1 supra 4 .

Answer 1

1) 3 -1/4 + 2/3 =
= (12×3 -3 + 8)/12 =
= (36-11)/12=
= 25/12

2) 3/5 - 1/15 + 4/5 =
= 7/5 - 1/15 =
= (3×7-1)/15 =
= 20/15 =
= 4/3

3) 1/5 - 1/6 + 1/15 =
= (6×1- 5×1 + 2×1)/30 =
= 3/30 =
= 1/10

4) 5/8 - 1/5 + 1/4 =
= (5×5 - 8×1 + 10×1)/ 40 =
= ( 25 - 8 + 10)/40 =
= 27/40